为了在光纤光栅匹配解调系统中实现对光纤光栅微弱信号的检测与处理,在应用微弱光电信号检测原理的基础上设计一种高信噪比、高检测精度的解调电路,该解调电路采用低噪声电路元件参数选取原则和前置放大器设计的一般方法,在雪崩光电二极管与信号数模转换之间采用互阻放大器、巴特沃斯滤波电路和多级放大电路,实现了电路的最佳噪声匹配,有效地抑制了电路的噪声和干扰.该解调电路在光纤光栅匹配解调系统中具有很高的信噪比和测量精度,且具有很好的灵敏度,在测量低频率振动信号试验中具有优异的性能.实验表明:该电路解调系统在25 ～200 Htz正弦激励振动信号下具有很好的低噪声性能,精确的测试出振动信号,同时该电路所采用的方法与措施对其他测量系统也有借鉴意义.%In order to achieve the fiber grating weak signal detection and processing in the fiber bragg grating matched demodulation system,the application of a weak optical signal detection theory,based on the design of a demodulation circuit of high signal to noise ratio and high detection accuracy, the demodulator circuit adopts the low-noise circuit element parameters selected principles and the general method of preamplifier design,thetransimpedance amplifier,butterworth filter circuit and multi-stage amplifier circuit were used to achieve the best noise matching circuit between the avalanche photodiode and digital-analog signal conversion, the circuit effectively suppress the noise and interference. The demodulation circuit has a high signal to noise ratio and accuracy, and has good sensitivity, low frequency vibration signal in the measurement tests with excellent performance. Experiments show that the demodulation circuit system in from 25 to 200 Hz under sinusoidal excitation signal has a good vibration, low noise performance,can accurately test the vibration signal,while the method of the circuit has reference for other measurement systems.
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